Merus N.V. (NASDAQ:MRUS) (“Merus”, “the Company”, “we”, or “our”), a clinical-stage oncology company developing innovative, full-length multispecific antibodies (Biclonics® and Triclonics®), today released clinical data on MCLA-145 from the phase 1 trial in patients with solid tumors at the ESMO Immuno-Oncology Congress 2021 being held virtually.
“We are encouraged by the progress we are making with MCLA-145,” said Dr. Andrew Joe, Chief Medical Officer. “Patients have been treated at 8 dose levels with preliminary evidence of antitumor activity observed, as we continue to explore MCLA-145 as monotherapy.”
MCLA-145
The reported data are from the phase 1 open-label, multicenter dose escalation study, of bispecific antibody MCLA-145 in patients with solid tumors. The primary objective is to evaluate the safety, tolerability, and dose-limiting toxicity (DLT) of MCLA-145 and to determine maximum tolerated dose (MTD) and/or recommended dose for expansion (RDE).
Observations in the presentation include:
- As of the data cutoff date of July 14, 2021, 34 patients with advanced or metastatic solid tumors with median age of 60.5 (range 27-81) years have been treated at 8 dose levels ranging from 0.4-75mg Q2W
- Median (range) duration of treatment with MCLA 145 was approximately 6 (1–74) weeks
- Reported adverse events (AEs) have been managed with drug interruption and/or administration of steroids in some patients
- Treatment-emergent AEs (TEAEs) occurred in 33 patients (97.1%); treatment-related TEAEs occurred in 23 patients (67.6%), most commonly fatigue (n=6, 17.6%) and decreased neutrophil count (n=6, 17.6%)
- DLTs defined as within 28 days from the first infusion occurred in 4 patients (11.8%)
- Laboratory alanine transaminase/aspartate transaminase (ALT/AST) elevations of any grade were observed in 15 patients (44.1%), with grade ≥3 ALT/AST elevations in 6 patients (17.6%)
- Preliminary evidence of antitumor activity has been observed at doses ≥25 mg biweekly
- Peripheral blood shows robust T-cell activation, including activation of cytotoxic CD8+ cells and cytokines, across the 10 to 75 mg biweekly dosing range
- Further evaluation of optimal dose and efficacy in PD-L1+ tumors is planned.
The phase 1 clinical trial of MCLA-145 consists of a dose escalation phase, followed by a planned dose expansion phase. MCLA-145 is the first drug candidate co-developed under Merus’ global collaboration and license agreement with Incyte, which permits the development and commercialization of up to 11 bispecific and monospecific antibodies from the Merus Biclonics® platform. Merus retains full rights to develop and commercialize MCLA-145, if approved, in the United States; and Incyte holds full rights to develop and commercialize MCLA-145 outside the United States.